Dual phase condenser system

ABSTRACT

The present invention relates to a dual phase condenser system, including an air-cooled portion, a water-air-cooled portion and a fan. The air-cooled portion can be further divided into two sectors, wherein the external air, drawn by the fan, passing through the second sector of the air-cooled portion first then to the water-air-cooled portion. The ability of air absorbing water vapor can be increased significantly in the water-air-cooled portion due to the increase of vapor pressure deficit (VPD) of the air passing through the air-cooled portion of the condenser. The dual phase condenser system of this invention is a 3-stage air-cooled condenser when shortage of water occurred. By separating gaseous and liquid refrigerants, the ability of removing thermal energy of the refrigerants can be increased. This invention required no extra fans, thus the EER can be increased when compared with the traditional one stage or patented two-stage air-cooled condenser. The dual phase condenser system of this invention is a 2-stage air-cooled plus 1-stage water-air-cooled condenser when water supply is not a constraint. This design retains the advantage of the water-air-cooled condenser when water is available and avoids its inherit disadvantage when no water is available or under humid condition, thus making it more functional than the patented water-air-cooled condenser.

FIELD OF THE INVENTION

[0001] Condenser is one of the devices in an air conditioning andrefrigerating system. It is a chamber for refrigerant to change statefrom superheated gas to saturated liquid and/or sub-cooled liquid bydissipating heat. This invention relates to dual phase condenser system,which consists of an air-cooled portion, a water-air-cooled portion anda fan. The air-cooled portion can be further divided into two sectors.Through the convergence of higher number of refrigerant pipes to a lessnumber of pipes, the gaseous and liquid refrigerants can be separatedbased on different compressibility. The amount of thermal energy removedof the refrigerants can be increased without using extra fans, thus theEER can be increased when compared with the traditional one stage orpatented two-stage air-cooled condenser. The water vapor absorbingability of air can be increased significantly in the water-air-cooledportion due to the increase of vapor pressure deficit (VPD) of the airpassing through the air-cooled portion prior entering to thewater-air-cooled portion. The air with higher VPD has the bettercapability to absorb moisture compare with the air not passing throughthe air-cooled portion of the condenser especially under the humidweather condition. The better capability of removing vaporized watersprayed on the surface of the condenser means capable of absorbing morelatent heat of vaporization. The combination of the above-mentionedportions allows the water-air-cooled portion still functional even underhigh humidity or no water available conditions, thus making it morefunctional than the patented water-air-cooled condenser.

PRIOR ART

[0002] The style of dissipating heat of the heat exchange device intraditional air conditioning and refrigerating system is the air-cooledtype and water-cooled type. The air-cooled type dissipates the sensibleheat by utilizing the temperature difference between external air andthe surface of the fins and pipes of the condenser. In addition, duringthe course of persistently dissipating heat of the air-cooled condenser,the temperature gradient, between air and refrigerants, becomes smallerand the efficiency of dissipating heat begins deteriorating, causing theliquid-vapor-ratio of the saturated refrigerants leaving the condensercannot be raised to a higher extent. This is the reason why the EER oftraditional air-cooled air conditioning and refrigerating system cannotbe considerably raised. In addition, during the course of dissipatingheat, liquid refrigerants and vapor refrigerants always co-exit in thecondenser. Therefore, both states cannot be efficiently dissipatingheat; moreover, a pressure loss caused from the friction between liquidrefrigerants and inner surface of pipe is often neglected, and thispressure loss results in great pressure drop before entering theexpansion valve. This is another drawback of such a traditional airconditioning and refrigerating system. In order to improve suchdrawbacks of the heat exchange device of the traditional airconditioning and refrigerating system, the conventional technique asshown in FIG. 1 is an air-cooled conditioning and refrigerating systemwith 2-stage condensers. The super-heated refrigerants leaving thecompressor 10, enters the 1st stage condenser 12 thru pipe 11. Aheat-dissipating fan 13, which is used to blow air into the 1st stagecondenser 12 for the purpose of dissipating heat of high temperature,superheated refrigerants. After the condenser performs heat exchangewith external air, the refrigerant converts from the superheated vaporstate into the saturated state with co-existence of liquid and vapor.The liquid-vapor ratio of the saturated refrigerant is increased alongthe pathway of the pipe. As it reaches the outlet of the 1st stagecondenser 12, the liquid-vapor ratio reaches the highest value. Then,the saturated refrigerant with co-existence of liquid and vapor entersthe 2nd stage condenser 15 thru pipe 14. Another fan 16 is used to blowair to the 2nd stage condenser. After completing the dissipation of heatat the 2nd stage condenser, it is ensured that the refrigerant reachessaturated liquid state or even reaches sub-cooled state. As shown bydotted line of FIG. 1, there are 2-stage condensers. Leaving the 2ndstage condenser, the refrigerant is sent to an expansion valve 18 viapipe 17. Passing through the expansion valve 18, the pipe pressure islowered and the temperature of the refrigerant is decreased. The lowtemperature and low pressure refrigerant is then sent to an evaporator19. During the almost isobaric process, the refrigerant absorbs thermalenergy from outside air. Non-evaporated refrigerant liquid and vaporflow from the evaporator into the accumulator 20. Vapor separated fromthe liquid within the accumulator, flows to the suction inlet of thecompressor 10 to complete a full cycle of the refrigerant of the wholesystem.

[0003] The above-mentioned 2-stage condensers includes; 1. The 1st stagecondenser equipped with regular fans; 2. The 2nd stage condenserequipped with high-speed fans; 3. A pipe with smaller diameter (neckpipe) connects two condensers. Due to the fact that the gas is much morecompressible than liquid, thus they can be separated after passing thruthe neck pipe. In an ideal operating condition, the superheated andsaturated vapor refrigerants retained in the 1st condenser and thesaturated liquid refrigerants flow into the 2nd condenser. The firstcondenser uses regular fans to dissipate heat. The temperature of theexhausted air of the 1st stage condenser is higher than the airtemperature passing through the condenser of a traditional airconditioning system. The capability of heat dissipating of the 2nd stagecondenser is not as good as the 1st stage, thus requiring high-speedfans to remove necessary amount of thermal energy with less pressuredrop within the system. Indeed, the above-mentioned 2-stage condenserscan considerably raise the ability of dissipating heat and got theinvention patent of Taiwanese (No. 129153) and U.S. Pat. No. 6,092,377.However, compared to the conventional air conditioning and refrigeratingsystem, due to the fact that this design requires extra condenser andextra high-speed fans, it increases power consumption; thus, there is nogreat improvement of EER.

[0004] Water-air-cooled condenser can remove more thermal energy ofrefrigerant due to the fact that the latent heat of vaporization is muchbigger than sensible heat. Taiwanese Patent No. 156031, as shown in FIG.2, includes a compressor 20, a condenser 21, a liquid storage vessel 22,an expansion valve 23 and an evaporator 24. Its closure cycle system isformed by many refrigerant pipes, wherein the condenser 21 furtherincludes: a water reservoir 25 which is situated below the condenser 21;a water supply pipe 26 one end of which is connected to the bottom ofthe reservoir 25 and the other end of which is extended to above andwhich is connected to pump 27, which sends water to the other end of thewater supply pipe 26; many nozzles 28 which installed on the watersupply pipe 26 above the condenser 21; fans 29 positioned on the top ofthe condenser shell; a feed pipe 30, the end of which runs thru the sidewall of the water reservoir 25 and the other end of which is connectedto a water source. Thus, the water is sprayed on fins of the condenser21, absorbing thermal energy from the fins of the condenser 21 and thenvaporizes. The water vapor is drawn to the outside by the fan 29.

[0005] It is expected that the EER of the water-air-cooled type airconditioning system is superior to those of air-cooled type if bothoperated in the design conditions. Various designs were made to improvethe water absorption ability on the surface of the fins and pipes of thewater-air-cooled condenser to further increase the EER of the system,for example, wrapping the refrigerant pipes with water absorbingmaterials. It is the same design that promotes the EER values thatlimited the amount of heat dissipation of the refrigerants if no watercan be supply. They show malfunction under suspension of water or highhumidity of external air. It can even arise potential danger if thepressure on the high-pressure side greatly increases due to poor heatdissipation.

[0006] Dry weather is ideal for water-air-cooled type air-conditioningsystem. However, under high humidity weather, especially, during therainy season, air humidity reaches as high as 90%, even 100%. The humidair has little space for water absorption, thus the capability ofremoving thermal energy of the refrigerants inside the condenser thruthe evaporative cooling process is greatly limited for the conventionalwater-air-cooled condensers.

SUMMARY OF THE INVENTION

[0007] Due to the above drawbacks, i.e. for the conventional air-cooledair conditioner, its energy efficiency EER cannot be greatly raised andfor water-air-cooled type, it cannot be normally operated during theshortage of water or in high humidity conditions. Therefore, the mainobject of this invention is to provide a dual phase condenser systemwhich can raise cooling efficiency without using extra energy and whichcan still be operated under suspension of water and under highly humidweather condition.

[0008] This invention relates to dual phase condenser system, whichconsists of an air-cooled portion and a water-air-cooled portion. Theexternal air is firstly pass through the air-cooled portion and then thewater-air-cooled portion. Within the first portion, the thermal energyof the refrigerant inside the condenser is removed due to the differenceof sensible heat. Within the second portion, thermal energy of therefrigerant is used to vaporize the water sprayed on the surface of thecondenser. The drier air, passing through the first portion, has thebetter capability to absorb moisture compare with the air not passingthrough the first portion of the condenser especially under the humidweather condition. The better capability of removing vaporized watersprayed on the surface of the condenser means capable of absorbing morelatent heat of vaporization. By combining two portions mentioned above,the dual phase condenser not only can greatly raise cooling ability withno extra energy consumption, thus increasing EER comparing withtraditional one stage or two stage air-cooled condenser, but also can beoperated if there is lack of water or under high humidity condition,thus making it more functional than the water-air-cooled condenser.

[0009] According to this invention, the air-cooled portion of the dualphase condenser is divided into two sectors accordance with the flowdirection of the refrigerant. High-pressure refrigerant, from the outletof the compressor, flows into several horizontal manifolds at the top ofthe first sector of the air-cooled portion. The refrigerant flowshorizontally, in a top-down fashion and converges at the end of thefirst sector, then enters the second sector of the air-cooled portion,flows horizontally and in a top-down fashion again. At the end of thesecond sector, the refrigerant converges again and flows into severalhorizontal manifolds at the top of the water-air-cooled portion of thedual phase condenser located at the back of the second sector of theair-cooled portion.

[0010] Within the pathway of the refrigerant inside the dual phasecondenser, it includes diminishing the flow path of refrigerant twice toconfine its flow. For example, refrigerants of 4 pipes converge into twopipes with same diameter and then converge to one pipe with samediameter. Due to the fact that gaseous refrigerant is much morecompressible than the liquid one, the superheated, saturated vapor,saturated liquid-vapor mixture and saturated liquid can be separated aspossible as it can be due to the existence of above-mentioned converges.It is possible that in the first sector of the air-cooled portion, therefrigerant is mostly in gaseous state, and in the second sector of theair-cooled portion, liquid and gaseous co-exist and it is liquid statein the water-air-cooled portion.

[0011] The dual phase condenser is a 3-stage air-cooled condenser whenshortage of water occurred and is a 2-stage air-cooled plus 1-stagewater-air-cooled condenser when water supply is not a constraint.Another merit of this invention of the dual phase condenser is that noextra fans required.

[0012] The dry bulb temperature of the Air passing through theair-cooled portion of the dual phase condenser will be increased and therelative humidity will be decreased, thus leading to the increase of thevapor pressure deficit (VPD) of the air. The values of VPD of the airindicate the water vapor absorbing capability. In rainy days withhumidity equals 100%, the VPD is 0. Air, before entering thewater-air-cooled portion, needs to pass through the second sector of theair-cooled portion to ensure that the VPD of the air will be alwaysabove zero, thus making it capable of removing thermal energy of therefrigerant in this portion even the outdoor environment is at 100%humidity.

[0013] One more merit of this invention of the dual phase condenser isthat the design retains the advantage of the water-air-cooled condenserwhen water is available and avoids its inherit disadvantage when nowater is available or under humid condition.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

[0014] For the purpose of illustrating the present invention, thefollowing drawings are provided. The above and other objects, featuresand efficiency of this invention will be further understood by readingthe description of embodiments in conjunction with attached drawings,wherein:

[0015]FIG. 1 is a construction view of conventional air-cooled aircondition system with two stages of condenser (Taiwanese Patent No.129153 and U.S. Pat. No. 6,092,377).

[0016]FIG. 2 is a construction view of a water-air-cooled airconditioning and refrigerating system (cited from Taiwanese PatentPublication No. 156031).

[0017]FIG. 3 is a perspective view of the dual phase condenser system ofthis invention.

[0018]FIG. 4 is an embodiment view of the embodiment of this invention,which is applied to the air conditioning system.

[0019]FIG. 5 is a perspective view of 5 equivalent variations of thedual phase condenser system of this invention.

DETAILED DESCRIPTIONS OF PREFERRED EMBODIMENT

[0020] Firstly, please refer to FIG. 3, the dual phase condenser system100 of this invention is consists of air-cooled portion 101 andwater-air-cooled portion 102. The air-cooled portion 101 constructed bymany tubes of the refrigerant and fins 120. Refrigerant inside theheader pipe 110 is branched into several horizontal manifolds in thefront section of the first sector 101. The purpose of this design is toshorten the flow path of the refrigerant and to decrease the number ofruns that passes thru the U-tube. The fins 120 dissipate heat byutilizing the sensible heat of the air. This air-cooled portion 101 isdivided into the first sector 101 a and the second sector 101 baccording to the flow direction of the refrigerant. The water-air-cooledportion 102 constructed by many tubes of the refrigerant and fins 120.In addition, a water pipe 130 is installed on an inner corner of theupper end of water-air-cooled portion 102. Water can be ejected throughnozzles or holes at certain interval on the water pipe 130. Mist or fogcan be sprayed to the fins 120 and pipes of the refrigerant. The thermalenergy of the refrigerant can be removed by providing the water with thelatent heat of vaporization. Valve 131 is installed in the water sourceof the water pipe 130. A timer 132 controls the valve 131 forintermittent water spraying. Fan 103 is used to draw external airflowing through the condenser for heat dissipation.

[0021] The second section 101 b of the air-cooled portion 101 ispositioned in front of the water-air-cooled portion 102. External air,blown in by fan 103, is heated firstly so as to increase the VPD, andthen it enters the water-air-cooled portion 102. The increase of VPDpromotes the ability of absorbing water vapor of air.

[0022] As shown in FIG. 4, the basic construction of this embodiment isthe same as that of conventional one. It includes: a compressor 111, adual phase condenser 100 which includes the air-cooled portion 101having first sector 101 a and second sector 101 b, a water-air-cooledportion 102 and a fan 103. The inlet of the condenser is connected tothe high-pressure side of compressor 111 by header pipe 110. Refrigerantinside the first sector 101 a flows horizontally in a top-down fashionand converges to two header pipes 110 a and 110 b, and then flows tosecond sector 101 b. Inside the second sector 101 b, refrigerant flowshorizontally in a top-down fashion and converges to one header pipe 110c, then flows to water-air-cooled portion 102. In water-air-cooledportion 102, refrigerant flows horizontally in a top-down fashion andconverges to one header pipe 110 d.

[0023] An expansion valve 112, whose end is connected to the outlet endof dual phase condenser 100 thru pipe 110 d, an evaporator 113 whoseinlet end is connected to the other end of expansion valve 112 by pipe110 e, an accumulator 114, the end of which is connected to the outletof evaporator 113 by pipe 110 f and the other end of which is connectedto the low pressure side of compressor 111 by pipe 110 g.

[0024] Water pan 133, positioned below the water-air-cooled portion 102,and in which there is provided with an exhaust water pipe 134 forexhausting surplus water.

[0025] Refrigerant converges in header pipes 110 a, 110 b and 110 cencountered restriction on the cross section area of the pipes. Flowpath of refrigerant becomes small to form a neck tube effect forconfining the flow of refrigerant. Liquid refrigerant is separated fromgaseous refrigerant. Under ideal operating conditions, superheatedgaseous refrigerant mostly concentrated in the first sector 101 a, thesaturated refrigerant (with high ratio of liquid-vapor) in the secondsector 101 b and the saturated liquid refrigerant in thewater-air-cooled portion 102.

[0026] The course of heat dissipating of the water-air-cooled portion102 mainly utilizes the mist or fog, sprayed from the nozzle installedat water pipe 130. Water droplets on the surface of the fins and tubesare heated to evaporate, thus indirectly removing the thermal energy ofrefrigerant.

[0027] Assuming the dry bulb and wet bulb temperature of external airare 35 and 30° C., respectively. The air is drawn into the second sector101 b of the air-cooled portion 101 by fan 103 and heated to 40° C. drybulb temperature before enters the water-air-cooled portion 102. Therelative humidity is reduced from 70% to 53% and the VPD is increasedfrom 1.67 to 3.435 kPa. The ability of absorbing water vapor is morethan doubled. Even in the rainy day with the humidity reaching 100%, drybulb temperature increased from 30 to 35° C. can result in the increaseof VPD from 0 to 1.38 kPa and decrease of relative humidity from 100 to75%. Allow external air passing through the air-cooled portion of thecondenser prior entering the water-air-cooled portion can overcome thedrawback of traditional water-air-cooled condenser.

[0028]FIG. 5 shows 5 types of embodiments of the dual phase condensersystem 100 of this invention. FIG. 5a shows the previously mentionedembodiment and other figures show 4 more embodiments with similarconstruction. Differences between 5 embodiments are the position of fan103 and the design of dual phase condenser 100.

[0029]FIG. 5a and FIG. 5b show the design of dual phase condenser 100,in which the air-cooled portion 101 and the water-air-cooled portion 102are combined into a unit.

[0030]FIGS. 5c, 5 d and 5 e show the design of dual phase condenser 100,in which the independent air-cooled condenser 101 and water-air-cooledcondenser 102 are connected in series. The first sector 101 a and thesecond sector 101 b of air-cooled condenser 101, shown in FIGS. 5c, 5 dand 5 e, may also be formed using two independent air-cooled condensers.In addition, either plain pipes or finned pipes can be used inwater-air-cooled condenser 102. Any available or future designs suitablefor water-air-cooled condenser can be utilized.

[0031] In the dual phase condenser system 100 of this invention, asshown in FIGS. 5a, 5 c and 5 d, fan may be installed in front of theair-cooled condenser 101 or installed at the rear end of thewater-air-cooled condenser 102, as shown in FIG. 5b and FIG. 5e. Inspite of the location of the fan, the air moves in the same direction.

[0032] While this invention has been illustrated and described inaccordance with preferred embodiments, it is recognized that variationsand modifications may be made therein without departing from theinvention as set forth in the claims.

[0033] In summary, the dual phase condenser system of this invention isa 3-stage air-cooled condenser when shortage of water occurred and is a2-stage air-cooled plus 1-stage water-air-cooled condenser when watersupply is not a constraint. This design retains the advantage of thewater-air-cooled condenser when water is available and avoids itsinherit disadvantage when no water is available or under humidcondition, thus making it a better design compare with patentedwater-air-cooled condenser. Also, the dual phase condenser required onlyone fan, thus making it a better design compare with the patented2-stage condenser in term of EER.

[0034] List of Elements:

[0035]100 the dual phase condenser system of this invention

[0036]101 air-cooled portion

[0037]101 a first sector of air-cooled portion

[0038]101 b second sector of air-cooled portion

[0039]102 water-air-cooled portion

[0040]103 fan

[0041]110, 110 a, 110 b, 110 c, 110 d, 1103, 110 f, 110 g pipes

[0042]111 compressor

[0043]112 expansion valve

[0044]113 evaporator

[0045]114 accumulator

[0046]120 fins

[0047]130 water pipe

[0048]131 valve

[0049]132 timer

[0050]133 water pan

[0051]134 exhaust pipe

What is claimed is:
 1. A dual phase condenser system includes anair-cooled portion and a water-air-cooled portion and a fan.
 2. The dualphase condenser system according to claim 1, wherein the air-cooledportion is divided into a first sector and second sector according tothe flow direction of the refrigerant, the piping of the refrigerantwhich comes from the high pressure side of the compressor being branchedinto many horizontal manifolds at the front section of the first sectorflowing from up to down, after the refrigerant converges at the top ofsecond sector, it runs horizontally and in top-down fashion and thenconverges again at the bottom of second sector, refrigerant then send tothe top of the water-air-cooled portion.
 3. The dual phase condensersystem according to claim 1, wherein one (or more) piping of watersource is (or are) installed on the internal corner of the upper side ofwater-air-cooled portion, and nozzles are installed or holes are drilledon such piping.
 4. The dual phase condenser system according to claim 1,wherein the refrigerant firstly flows to the air-cooled portion, theninto the water-air-cooled portion.
 5. The dual phase condenser systemaccording to claim 1, wherein the refrigerant firstly flows to thewater-air-cooled portion, then into the air-cooled portion.
 6. The dualphase condenser system according to claim 1, wherein in spite of thelocation of the fan, air is drawn into the air-cooled portion first theninto the water-air-cooled portion.
 7. The dual phase condenser systemaccording to claim 1, wherein the dual phase condenser system isconstructed by connecting, in series, an independent air-cooledcondenser and independent water-air-cooled condenser.
 8. The dual phasecondenser system according to claim 2, wherein the first and the secondsectors of the air-cooled portion are constructed using two independentair-cooled condensers.